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To study the mass transport of mucociliary clearance of the human upper respiratory tract, a two-dimensional mass transport model based on the ciliated movement was established by using the immersed boundary-lattice Boltzmann method (IB-LBM). In this model, different characteristics of the mucus layer (ML) and the periciliary liquid (PCL) were taken into account. A virtual elastic membrane was introduced to divide the two layers dynamically. All moving boundaries that were involved in the present simulation were modeled with the immersed boundary. The Newtonian fluid was used to model the flow in PCL, and the viscoelastic fluid based on the Oldroyd-B model was used for the flow in ML; the two types of flow were both solved by the LBM framework. Based on the model, the ML thickness, the cilia density, and the phase difference of adjacent cilia were regulated, respectively, to study the transport velocity of the ML. In addition, the motion law of solid particles in PCL was also studied. According to the results, four primary conclusions were drawn. (1) At a given beating pattern, the increase of the ML thickness will decrease its transport velocity. (2) Increasing the cilia density can promote the mean transport velocity of the ML. (3) By raising the phase difference of adjacent cilia to a certain scope, the transport of ML can be accelerated. (4) In PCL, particles initially located on the upper part of the cilia tend to migrate upward and then get close to the ML. The above study can provide some reasonable explanations for the mechanism of the mucociliary clearance system, which is also helpful to the further understanding of the mass transport principle of the human upper respiratory tract.

This paper presents an adaptive sliding mode control for trajectory tracking of quad rotor aerial robot with I type configuration. A continuous adaptive dynamic vector is used to eliminate the chattering phenomenon in the sliding mode control and the asymptotic stability is achieved. On the base of a nonlinear dynamic model of the quad rotor with I configuration, adaptive sliding mode nonlinear controller is synthesized for the purpose of stabilization and trajectory tracking of quad rotor. In order to validate the robustness of the proposed control method, the model deviations are modeled. It behaves perfectly at the reference altitude and trajectory track in simulation.

In this paper, a two-dimensional dynamic model of human respiratory cilia is established by immersed boundary-lattice Boltzmann method. In the model, periciliary liquid and mucus layer with different flow characteristics are considered, in which the non-Newtonian fluid in the viscous layer is described by Oldroyd-B model; the area between two layers is dynamically divided by a virtual membrane. By changing the cilium beat amplitude and the depth of periciliary liquid, this paper focuses on the removal of particle impurities by cilium beat. The results show that when the initial position is near the top of cilium, the particle tends to migrate upward to approach the mucus layer. However, if the initial position is near the middle or at lower part of the cilia, most of the particles will not be transferred to the vicinity of mucus layer by the swinging cilium. It is also found that by increasing the beat amplitude of cilia, particles are more likely to approach the mucus layer. By conducting this study, the migration of the particle in periciliary liquid is discussed in detail. The results are significant to help us to know the material transport law of human respiratory tract.

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This paper reports on an efficient lossless compression method for periodic signals based on adaptive dictionary predictive coding. Some previous methods for data compression, such as difference pulse coding (DPCM), discrete cosine transform (DCT), lifting wavelet transform (LWT) and KL transform (KLT), lack a suitable transformation method to make these data less redundant and better compressed. A new predictive coding approach, basing on the adaptive dictionary, is proposed to improve the compression ratio of the periodic signal. The main criterion of lossless compression is the compression ratio (CR). In order to verify the effectiveness of the adaptive dictionary predictive coding for periodic signal compression, different transform coding technologies, including DPCM, 2-D DCT, and 2-D LWT, are compared. The results obtained prove that the adaptive dictionary predictive coding can effectively improve data compression efficiency compared with traditional transform coding technology.

In the regional multiairport system, the contradiction between the limited operating resources and the large flight flow is serious, and the flight delays can easily lead to the occurrence of unsafe events. This paper investigates the abnormal flight recovery method in regional multiairport system based on risk control. The focus is to reschedule arrival-departure flights in real time with minimized delay time and risk probability. In this study, the risk about terminal area control and scene operation was considered in the analysis of the risk control model (RCM), which includes six key risk points: airspace control, flight conflict, ground service, apron support, ground control, and taxiing conflict. The mathematical model on flight recovery was constructed to solve minimized delay time and risk probability with MSINS (multistart algorithm with intelligent neighborhood selection). The data of a typical regional multiairport system in China were selected for experimental verification in order to compare the RCM with the traditional recovery model (TRM). The experimental results show that first, there are some hidden dangers in the traditional recovery methods of flight delay. Flight conflict and apron support are the risk points that need to be controlled most in the multiairport system. Secondly, for the effective solution with the shortest delay time, the RCM can reduce the overall operation risk of the system, but the flight delay time is a little longer. For the effective solution with the lowest risk probability, RCM can reduce the risk of system operation and the delay time of flights at the same time. Therefore, RCM can improve the security level of the system during abnormal flight recovery and ensure or even improve the recovery efficiency.